Cancers have been a disease that occupies the first position in the list of causes of death of the Japanese since 1981 and the number of patients of this disease has been increasing thence year after year. The basic research and clinical research regarding the therapy of cancer has been advancing on the global level over these 10-odd years. This development in association with the advance of the diagnosis of cancer has been making it feasible to ensure early detection and treatment of a cancer.
The therapy of cancer is based on a surgical operation, a radiotherapy, and a cancer chemotherapy (therapy using an anti-cancer agent). The cancer chemotherapy is a method for treating malignant neoplasm by the administration of an anti-cancer agent. Since an anti-cancer agent has no substantially different effects between cancer cells and normal cells, side effects thereof become severe in accordance with the improvement of treatment effects. Cisplatin, for example, has serious side effects such as renal dysfunction, nausea, vomiting, neuropathy, myelopathy like leukopenia, thrombocytopenia, and anaemia. The manifestation of such side effects which are caused by the cancer chemotherapy often entail such a situation as limiting the dosage of an anti-cancer agent and discontinuing the therapy. Further, the restraint of the side effects has an important influence on the life lengthening of a patient under treatment. In the execution of the cancer chemotherapy, therefore, it is a very important task to decrease the side effects without repressing the effects on the treatment with an anti-cancer agent.
As medicines for decreasing the side effects by the therapy with an anti-cancer agent, such 5-HT3 acceptor antagonists as granisetron and ondansetron which are effective for nausea and vomiting and such bone marrow function activators as filgrastim and lenograstim which are effective for leukopenia have been known. In the field of cancer chemotherapy, the desirability for developing a novel ameliorating agent for cancer chemotherapy which enhances the carcinostatic action of an anti-cancer agent and represses various side effects thereof has been still finding popular recognition.
The chromanol glycoside which is used in this invention is a known compound (JP-A-7(1995)-118287, JP-A-9(1997)-249688, and JP-A-11(1999)-21291). The chromanol glycoside results from substituting an alcohol for the phytyl group at the 2 position of a chroman ring of a representative example of Vitamin E, α-tocopherol, and further linking saccharide thereto and has high water-solubility and excellent antioxidizing ability. The use of this chromanol glycoside as an ameliorating agent for the cancer chemotherapy, however, has never been known heretofore.
This invention has been attained in consideration of the problems of the prior art as described above. It is an object of this invention to provide a novel ameliorating agent for cancer chemotherapy which effectively functions safely in a small amount and exhibits excellent ability of repressing various side effects entailed by the cancer chemotherapy.
Another object of this invention is to provide a novel ameliorating agent for cancer chemotherapy which enhances carcinostatic function of an anti-cancer agent in the cancer chemotherapy.